Verdict

For a NAS cache or write-heavy pool, the ZA4000NM1A002 is the safer pick - the WDS400T4B0E uses QLC NAND, which wears out faster and slows badly under sustained writes (light, read-mostly use only).

WDS400T4B0E
WD Blue SN5000 · 4TB · Desktop
$490 ($122.50/TB)
ZA4000NM1A002
Seagate IronWolf 125 · 4TB · NAS
No US price yet

Value at a glance

Endurance (TBW)
WDS400T4B0E 1,200 TB
ZA4000NM1A002 5,600 TB

Price history

US · cheapest per day

WDS400T4B0E $490
zoomed · drag to zoom
$490 $466 $443 Aug 25 Aug 29 Sep 2 Sep 7 Sep 11 Sep 16
WDS400T4B0E ZA4000NM1A002
Capacity 4 TB 4 TB
Form factor M.2 2.5
Interface NVMe SATA
NAND type QLC TLC
Endurance (TBW) 1,200 TB 5,600 TB
DWPD - 0.7
DRAM cache No Yes
Power-loss protection No No
Sustained write - -
Cost / TBW $0.405 -
Price / TB $121.36 -
Buy
$490
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No US price yet

Highlighted cells mark the stronger spec for a NAS build. Failure rates from Backblaze Drive Stats where available; $/TB uses the cheapest live price. Buy links are Amazon affiliate.

WDS400T4B0E

No Backblaze failure data for this model.

ZA4000NM1A002

No Backblaze failure data for this model.